Distance measurement method for power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation

A single-phase ground fault, line-mode traveling wave mutation technology, applied in the fault location, using the pulse reflection method to detect faults and other directions, can solve the problems of ranging errors, false fault points, and high instability of the distribution network system, to achieve The effect of reducing random interference and improving accuracy

Inactive Publication Date: 2014-05-21
SICHUAN UNIV
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Problems solved by technology

[0004] For a power distribution network with a complex structure, the signal received by the detection end is the superposition of multiple refraction and reflection waves at the fault point, branch point, and branch end. It is difficult to find the reflected wave at the fault point only by using the waveform obtained after fault phase injection. The following two methods are used to extract the reflected wave of the fault point: one is to inject a high-voltage pulse signal into each phase before the system fails to obtain the non-faulted traveling wave waveform of each phase and store it, and inject the same wave into the faulty phase after the line fails The waveform of the fault condition is obtained by the high-voltage pulse signal, and the two sets of waveform data obtained by the fault phase and the non-fault condition are subtracted to extract the fault informatio

Method used

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  • Distance measurement method for power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation
  • Distance measurement method for power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation
  • Distance measurement method for power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation

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Example Embodiment

[0043] Example 1:

[0044] A method for locating single-phase ground faults in distribution networks based on line mode traveling wave mutations, including the following steps:

[0045] (A) Inject the same high voltage pulse at the head end of the distribution network at the same time, and detect the three-phase return voltage traveling wave; the injected high voltage pulse is a high voltage pulse with pulse width Xμs and amplitude YkV, such as image 3 , The three-phase return voltage traveling wave is detected;

[0046] (B) Use the traveling wave of each phase voltage obtained in step (A) The transformation formula is to transform the phase mode transformation matrix to the modulus, and S uses the Karen Bower transformation or Clark transformation matrix to obtain the line-mode voltage traveling wave;

[0047] (C) Perform differential derivation of the line mode voltage traveling wave obtained in step (B) to obtain the time of the first non-zero mutation point, and then obtain the t...

Example Embodiment

[0065] Example 2:

[0066] Such as figure 1 As shown, this embodiment is an experiment for single-phase grounding fault location in a distribution network, using frequency dependent line models (Frequency Dependent Models) in PSCAD (Power Systems Computer Aided Design); figure 2 It is the structure diagram of the experimental circuit. A is the head end of the line (that is, the detection point). Each branch end is connected with a 10kV / 0.4kV distribution transformer (Dyn or Yyn connection) and a three-phase unbalanced load. The sampling frequency is 10MHz. The setup failure occurred on figure 2 The EI section of the line from point E to point I has a ground resistance of 100Ω and a distance of 17km from the head end.

[0067] First, inject a high voltage pulse with a pulse width of 4μs and an amplitude of 10kV at the head end of the line at the same time to obtain the three-phase voltage traveling wave signal returned by the line, such as image 3 Shown; use Correct image 3 The...

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Abstract

The invention discloses a distance measurement method for a power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation. The method includes the following steps that (1) the same voltage pulse is simultaneously injected to three phases of a head end of a power distribution network, and voltage traveling waves returned from the three phases are detected; (2) the voltage traveling waves of each phase, which are obtained in the step (1), are transformed to modulus by a phase-mode transformation matrix, and further, aerial mode voltage traveling waves are obtained; (3) the aerial mode voltage traveling waves obtained in the step (2) are subjected to difference derivation to obtain first nonzero mutational point time, and thereby, travel time of the traveling waves can be obtained; (4) the travel time obtained in the step (3) is substituted into a distance measurement formula to obtain fault distance. According to the method, high voltage pulse is simultaneously injected to the three phases of the head end to detect aerial mode voltage traveling wave mutation so as to perform fault distance measurement, and thereby, the problem of fake fault points caused by unbalance three-phase loads of the distribution network is solved.

Description

technical field [0001] The invention relates to a traveling wave ranging method, in particular to a method for injecting traveling wave ranging based on a single-phase grounding fault of a distribution network based on a line-mode traveling wave mutation. Background technique [0002] my country's 6~35kV distribution network generally operates in the neutral point non-direct grounding mode. After a single-phase ground fault accounts for 50%~80% of the total faults, the traditional processing method uses manual line inspection to find the fault point, which is time-consuming and laborious. Research on accurate and effective single-phase ground fault location method is of great significance for improving the power supply reliability of distribution network and reducing power failure loss. [0003] At present, there are two main development directions of distribution network fault location methods: the method based on distribution network automation system and the traveling wav...

Claims

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Application Information

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IPC IPC(8): G01R31/11
Inventor 舒勤周聪聪钟俊韩晓言董丽梅
Owner SICHUAN UNIV
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